It has been an interesting year for navel orangeworm (NOW) pressure in almond orchards. Independent PCA with Valley Ag Consulting Services, Tracy Miller said that trap counts were much higher at the start of the season. Several factors could be responsible for the irregular trapping trends. The lack of rainfall in the winter along with warmer temperatures in early spring may have allowed many overwintering larvae to survive.
Trap counts have generally declined in recent weeks after significant levels were seen initially. Miller said that growers will want to be paying close attention to when the second-generation flight of NOW will begin to emerge. The large numbers of NOW seen in orchards early in the season could occur again as hull split approaches.
“It’s really important that they know when that’s going to start to occur because we can expect that when the second-generation flight does occur, it’s going to be very big,” Miller explained. “It’s going to mimic what we saw with the overwintering generation.”
As of right now, hull split is expected to commence sometime around the second week of July. Depending on temperatures, there is a chance that the second generation of NOW could come early and miss hull split. However, Miller said that in most years the second generation flight and hull split have generally been in sync. In that case, growers will want to be ready with their applications.
“If they are late on getting their hull split insecticide on, they’re going to be in trouble because we’re going to see a mass amount of egg-laying that occurs very early this year,” Miller noted. “So, these eggs are going to be laid, as soon as that nut splits, those worms are going to be ready to go in. If growers are a little bit late this year, I think it could be devastating.”
Listen to Miller’s full interview.